Hi my galaxy tabA installed an update last night and now won't go past the Samsung screen have done the power and vol- reset but then goes back to logo has been like it for over 10 hours.
It might well be that the update is simply taking the time to rewrite the current firmware with the newly-downloaded firmware. Power on the device, and go make a cuppa or something. After 30 minutes, if the screen hasn't changed, then perform a hard reset.